Screen for coal or other material



(No Model.)

J. N. POTT. SGREEN FOR GOAL OR OTHER MATERIAL.

Patented July 30, 1895.

UNITED STATES PATENT OFFICE.

JOHN N. POTT, OF CHICAGO, ILLINOIS.

SCREEN FOR COAL OR OTHER MATERIAL.

SPECIFICATION. forming part of Letters Patent No. 543,780, dated July30, 1895.

I Application filed October 11, 1894. Serial No. 525,591. (No model.)

To all whom it may concern.-

Be it known that I, JOHN N. POTT, a citizen of the United States,residing at Chicago, in the county of Cook and State of Illinois, haveinvented new and useful Improvements in Screens for Coal or otherMaterials, of which the following is a specification.

This invention relates to perforated-metal screens for cleaning andsizing coal, coke, ores, gravel, stone, &zc.

The object of the invention is to provide the screening or workingsurface of a perforatedmetal screen-plate with an effective arrangementof rounded protuberances or protrusions, forming double reverse curveswith the plate, distributed at suitable intervals and located atintersections of the portions of metal left between the holes that areformed through the plate. By this construction there is provided anuneven screening-surface which will prevent the material being screenedfrom passing over it in mass and that will cause a slight undulatorymovement in the said ma terial, thereby assisting the smaller particlesto descend to the surface of the screen, so that such as are smallenough may readily pass through. The protuberances will also prevent thelarger lumps of material from coming in contact with the sharp edges ofthe holes in the screenplate, thereby avoiding considerable waste, asfrail materials are liable to be broken by striking against such edges.

Other advantages of the invention, in simplicity and comparatively smallcost of the screen and in the economy and efficiency of its operation,will hereinafter more fully appear.

My invention consists in a perforated-metal screen-plate having itsworking surface provided at intervals with rounded protuberan cesforming double reverse curves with the plate and located at some or allof the intersections of the portions of metal left between theperforations of the plate, whereby the cleaning and sizing of variousmaterials are facilitated and the breaking of large lumps prevented, ashereinafter described and claimed.

In the annexed drawings, illustrating the invention, Figure 1 is aperspective of a portion of a perforated'metal screen-plate havingsquare holes arranged in parallel lines both lengthwise and crosswise ofthe plate and provided on the working surfacewith protuberances that arestruck up from the plate at all the intersections of the portions ofmetal left between said holes. Fig. 2 is a sectional view of the screenon the lines 2 2 and 2 2 of Fig. 1. Fig. 3 is a plan of a portion of ascreen similar to that shown in Figs. 1 and 2, except that theperforations are smaller and the protuberences are located only at someof the intersections of the portions of metal left between theperforations, preferably at every other intersection. Figs. 4 and 5 arerespectively sections on the lines 4 4 and 5 5 of Fig. 3. Fig. 6 is aplan of a portion of a screen having circular perforations and providedon its working face with rounded protuberances arranged at suitableintervals in spaces or intersections of the plate between perforations.Fig. 7 is a section on the line 77 of Fig. 6. Fig. 8 is a plan of aportion of a screen having oblong holes and provided on its workingsurface with protuberances located upon or struck up from the metalbetween the ends of said holes and suitably spaced. Fig. 9 is a sectionon the line 9 9'of Fig. 8.

In asserting coal, gravel, ores, and other materials it is customary toemploy screens composed of perforated metal plates or sec tions havingsuch form and dimensions as will best adapt them for attachment totheframe of a preferred kind of screen, whether revolving, chute, shaking,oscillating, or gyrating. Perforated-metal screen-plates are moredurable than woven-wire screens; but in order to prevent the materialbeing screened from sliding off in mass it is desirable that the workingsurface of the screen-plate should be made somewhat uneven orirregular.The punched apertures of a perforated metal screen-plate by reason oftheir sharp edges are liable. to cut up or break the larger pieces ofany frail material thrown or forced against them, and for the purpose ofobviating this objection it is of great advantage to so form and arrangethe irregularities of the screening-surface as to keep the large lumpsof material away from the screen-openings, thus preventing breakage andwaste and at the same time permitting the small particles of material topass readily to and through the screening-apertures.

I have shown in Figs. 1 and 3 portions of perforated-metal screen-plates12, provided with substantially square holes 13, arranged preferably inparallel lines both lengthwise and crosswise of the plate. Theperforations 13 may be formed in the metal plate by cutting or punchingin any well-known manner.

On the working surface of the screen-plate 12, at intersections of theintegral webs 14, or portions of uncut metal left between theperforations 13, I form a number of spaced-apart and roundedprotuberances 15,1l1at are integral with the webbing portions of theplate from which they are stuck up or protruded and are so shaped as toform double reverse curves. The humps or protuberances 15 are preferablyformed by the pushing outward beyond the working face of thescreen-plate of portions of metal subjected to the pressure of a roundor oval ended punch applied to the opposite face of the plate. If thescreenplate is provided with perforations of a large size-say one inchor more across-as shown in Fig. 1, the protnberances 15 on the workingface of said plate maybe advantageously located at all the intersectionsof the webs or portions of metal left between the perforations. Wherethe square perforations are smallersay under one inch across-as in Fig.3, the protnberances 15 will be preferably located only at every otherintersection of the intermediate webbings, or they may be formed at suchintersections as will afford the required spacing to enable theprotuberanccs to serve as guards for the perforations through the plate.

Instead of square perforations the screenplate may be provided with anysuitable arrangement of circular holes 16, Figs. 6 and 7, with the humpsor rounded protuberances 15 located at such intervals as may be requiredand in spaces between the holes at intersections of the webbing by whichthey are separated.

As shown in Figs. 8 and 9, the screen-plate may be formed with oblongperforations 17 of any preferred size, and the protrusions orprotuberances 15 will be located upon the working face of the plate, inthe metal between the ends of the oblong holes, and may be spaced apartas desired.

It will be observed that in each variety of screen illustrated in thedrawings the rounded humps or protuberances 15 are located on theworking face of the screen at intersections of the webbing between theperforations or screen-holes. These protuberances are integral with andprotrude beyond the working face of the screen in such manner as to formdouble reverse curves therewith and may be spaced apart or arranged atany suitable intervals to impart the required irregularity or unevennessto thescreening-surface. By reason of the irregularities of surface thusproduced the material to be screened is prevented from rapidly slidingoff from the screen, and receives a somewhat undnlatory and retardingmovement that facilitates the passage of the smaller particles towardand through the screen-perforations.

The rounded protuberauccs 15 not only retard the slid ing movement ofmaterial on the screen but they also act as guards to keep the largerlumps away from the screen openings or holes. In this way a more freepassage is afforded for access of small particles to thescreenapertures, thereby rendering the operation of screening morethorough and'effective. At the same time a wasteful breakage or cuttingto pieces of large lumps from contact with sharp edges of punchedscreen-holes is avoided; and it will also be observed that as theprotuberances 15 are rounded and rise gradually from the metal platethey present no sharp angles, points, edges, or projections that wouldbe liable to break up large pieces of material and thus add to thewaste, as in some forms of construction.

The rounded protuberances 15 may be formed on the working face of thescreenplate, in the intersections of the webbing, at

the same time that the perforations are out.

or punched. This may be readily accomplished by means of any suitablepunching or die mechanism.

It is obvious that the screen-plates or sections may be either flat orsomewhat curved, according to the characterof screen in which they areto be used.

The perforated screen plates, with the rounded protnberances, shaped toprevent double reverse curves in section, may be formed from anysuitable sheet metal by means of appropriate punching devices, or theymay be made by casting if preferred. In this construction the perforatedscreen plates are comparatively simple and inexpensive, while the formand distribution of the gradually-rounded protuberanccs on the workingsurface will effect economical results in the screening, cleansing andsorting of various materials without breakage and consequent Waste ofthe larger pieces or lumps.

What I claim as my invention is- The herein described metal screen platehaving rounded protuberances forming double reverse curves with saidplate and located on and integral with its Working surface atinter-sections of the integral webbing or portions of metal left betweenthe perforations, the said rounded protubcrances being spaced apart toserve as guards for the perforations and prevent breakage of large lumpsor pieces of material being screened and to impart a retarded undulatorymovement to the material that will preventa rapid sliding off from thescreen and facilitate the passage of smaller particles through theperforations of the screen, substantially as specified.

In testimony whereof I have hereunto set my hand and affixed my seal inpresence of two subscribing witnesses.

JOHN N. lO'lT. [L. s]

Witnesses:

EDWARD RUHE, S. A. BUTZ.

IIO

